Subwoofer EQ'ing, Behringer PRO DSP 1124P

[Beatmatcher247]

I'm trying to tame what appears to be some massive dips and peaks in a somewhat problematic room.


Looking at the Behringer Pro DSP 1124P
http://www.realproaudio.com/feedback-destroyer-p-961.html

LOoking at using this to tame my (2) JL Fathom F113's. Is this adequate equipment for the job? Any other products you subwoofer gurus would recommend over this ?

 

[Warpdrv]

massive dips -

^^^This is a problem^^^ You never want to boost massive dips....
yes the 1124 will be fine for EQ

From the PM you sent me, it sounds like you are pushing the limits of your subs and driving your amps into clipping which is why your subs are "farting" that is the limiter built into the amp which will protect the driver....

2 things, 1 you need to start either working on better placement to get rid of some of those peaks and dips and you can't be boosting the nulls - which will strain the amps to deliver what you are looking for in your room, only pull down the peaks to get as smooth as you can...

It might be time for you to be looking at different / larger subs to fill your needs in the bass dept - a pair of the 18" LMS's might just be the ticket here for you... Your problems with the LFE scenes in certain movies is 2 fold - 1, the subs are high passed internally and will roll off or kick in the limiters below 18hz, so you get nothing below that and many a movie these days has huge material below that point... Placement can assist in possibly fixing those nulls or bass traps to absorb the cancellation that is going on... Then EQ after you find the best placement.

Perhaps you have outgrown the JL's, which is what I had - and It might be time for you to be looking at different / larger subs to fill your needs in the bass dept - a pair of the 18" LMS's might just be the ticket here for you, which have a touch better SQ but FAR more output then the JL's... You can get the drivers at PE, have Nathan at Funky Waves build you a pair of cabinets and use external amps like I do for a pretty good bargain. A pair of EP4000, 1 for each will likely be more then you need for this project.

 

[Beatmatcher247]

I don't know all that much about eq'ing subs warp. Why don't you want to boost the nulls?

Anyway to disable their highpass filter and do it all with the behringer? So it sounds likely to you the material I'm experiencing some problems with is asking them to dig too low?

I'll likely not be attempting a DIY build till I build a room that can handle the assault proper in about 5 years or so when I do my first custom home. It looks though like that replacing the JL's will be inevitable at some point. Wish I would have listened. Hope I can recover some of that wad I spent on them when I get to that point.

 

[gmichael]

I don't know all that much about eq'ing subs warp. Why don't you want to boost the nulls?

Anyway to disable their highpass filter and do it all with the behringer? So it sounds likely to you the material I'm experiencing some problems with is asking them to dig too low?

I'll likely not be attempting a DIY build till I build a room that can handle the assault proper in about 5 years or so when I do my first custom home. It looks though like that replacing the JL's will be inevitable at some point. Wish I would have listened. Hope I can recover some of that wad I spent on them when I get to that point.

Nulls are usually caused by location + room conditions. The waves are reflecting off the walls and meeting in such a way that some frequencies get canceled out. That's what's causing the nulls. Boosting doesn't help because you're just making bigger waves that do more canceling while taxing your poor amp to death.

Try moving the sub to see what you get.

 

[Warpdrv]

Boosting the nulls will be asking the amp to deliver double the amp power at that certain freq for every 3db you boost ( pretty sure about those numbers, correct me if I'm wrong people) which will drive the amp into clipping faster then normal.

There is no way to disable the HP filter on the JL subs, its built into the amp to protect the driver - end of story.

Moving over to the LMS's could be almost a sideways move monitarily for you... If you were to sell those JL's, I estimate you get $2K for them each. Figure about $1k for each box from nathan, or cheaper for diy, $925 each from the LMS's and a few hundred for the amps.....

Just saying - this way you retain or rather improve the SQ you are already used too..... plus you more then quadruple (closer to multiple of 6x) the output to best suit your needs, which you obviously don't necessarily need, buuuuut its always better to have it and not need it, then to need it and not have it - like where you are now....

 

[Beatmatcher247]

I'm going to post some pictures of my room. RIght now I got a Sub in the front left corner, with a couch about 3' in front of it and a big entertainment center to the right. So it doesn't have a lot of space around it in any direction. These couches and the entertainment center are very large and very solid. Could having it too "boxed in" cause me any of these sorts of problems?

When I get my behringer and do some sweeps with a much more knowledgeable friend of mine, we'll find what works best for placement and see what we can do to improve things. We're going to check for phasing problems too.

 

[Warpdrv]

Room dimensions as well sir.... openings to other areas or closed off.. ?


I like friends - they assist me in the needs I have to help me build cool stuff - This friend of yours, any chance you guys could come up with some way to build new sub boxes. $70 a sheet for good baltic birch ply - 1 of those needed for each box. Cut, Glue, stuff - mount driver...

I started out with test boxes before I bought any of my sexy custom boxes. I recently sold them off to my friend so he could use them in his room for LMS's. He is thrilled - replaced his Submersive with them.

 

[Beatmatcher247]

My handiwork looks like homer simpson's spice wrack. I would definately be going with a funkywaves from Nathan before I'd try to build my own. This is a ways down the road too. First I want to fully exhaust all resources trying to get my F113 moneypits to able-to-live-with-for-a-while status.

 

[Warpdrv]

understood and agree- just wanted to point out that the product listed on Funky Waves site isn't the only way to skin a cat - it can be far cheaper if one is willing to do a bit of work....

I agree - you really should exhaust all methods before just pulling the trigger...

In your case - first thing I would do it run ARO on both subs unless your tying them together and one is master - next is slave - and run ARO just 1 time....

Then hit up the EQ realm and see what your results are after the fact - post up results here for suggestions - pull down all the peaks with eq then level match or run however hot you feel you like after EQ and see how that works out for you....

What is your room size here...?

 

[Beatmatcher247]

I'll get you pics and dimensions tonite and postem tomorrow.

 

[Beatmatcher247]

Pics of my room, including shots of suckout areas. I'll post dimensions in the next post.

 

[Beatmatcher247]

Room is basicallly rectangular shaped measuring 25' x15'... the lower right hand corner juts out 5 feet wider for an additional 30 sq. feet... ceiling heighth is approximately 8' high. I took some pictures of the suckouts that I have. I know this room is less than ideal but it is what I have for the next 5 or so years. Don't mind my mess or my shipping crate speaker stands... those are a work in progress as well as some nice dark wooden blinds with a complete blackout sheet behind them that will velcro up there during movies.

 

[j_garcia]

So, one behind you and one (or two?) in the front left corner?

I've used the BFD before and it works well, but as Warp said, you don't want to be boosting nulls. I would definitely try different locations (co-locate) for the subs first, then DSP if necessary.

What receiver or pre/pro are you using? Does it not have auto-calibration and EQ like Audessey? That can often help also. It looks like a Marantz or Denon unit in there.

 

[Beatmatcher247]

I've got one sub directly to the left of the primary seating position, and another in the front left corner by my htpc. I used to have it in the front right but moved it to the left corner to experiment.

It is a Marantz AV7005. I love the way my mains sound without applying the correction software. If it's not broke, I don't want to try and fix it. I will handle my subwoofers seperately.

 

[Warpdrv]

I agree - perhaps you can try to stack those bad boys in the corner and see how things go like that.... you will gain 6db by colocating them.... Might help with your nulls as well.. I'm wondering why in your space that you'd be having problems with them not producing enough bass... they should be up to the task... room size is roughly a bit more the 3000^3...

Did you already run some sweeps that you know you have some major peaks and nulls - can you post a pic of the sweep..?

 

[Beatmatcher247]

I don't know how to run sweeps or any of that. All I know how to use is my ears and a dB meter. A friend who is more knowledgeable is going to come over and help when I get my Behringer. I'm going to bribe him with some championship grade bbq loin back ribs slow smoked with apple and hickory chips.

You see the stairs going up, and the stairs going down? Those are my big suckouts. I'm also concerned about how that wall that juts in the back right corner comes into play. I'm just assuming i've got dips and peaks cause it sounds so inconsistent throughout a curve. I know my subs sound way louder if that bathroom door to the right of the tv is closed too.

First glance though, the front left corner would be the best spot in your opinion warp? I know it's impossible to say for sure without setting it in the seating position and crawling for bass. It sounds like the majority of the wompiness is coming from that corner whereas the one to the left of the primary seat position doesn't sound as distressed. That "boxing" that one in the corner so much mess with things?

 

[Warpdrv]

I rarely would say just throw them in a corner and see how it sounds but at this point you don't have much options.

IMO - just looking at the room stacked or side by side (doesn't matter) behind the right main might be an improvement as the wall seems to then fade away and perhaps it won't be trying to corner load the opposite corner as heavily - which in this case is down into the stairway, quite possibly might be a better option...

I think you'll get smoother bass with then not separated - IN THAT PARTICULAR ROOM....

 

[Beatmatcher247]

When my buddy stops by we're going to set it on the primary listening position seat and crawl around trying to find out where the best spot is. In the mean time, I'll stack them both in that right corner and see how that goes for a while. Maybe I'll spin that movie up that I had problems with, Lord of the Rings (the fellowship of the ring), and see how it does in that corner stacked.

Stacking will resolve phasing issues too, no? if I have them both set to the same phase setting? Regardless of master, master, or master/slave configuration?

Thanks everyone for your advice.

 

[Warpdrv]

If they are in the same llocation I would set the to the same phase - 0
Just double check with an split meter on ttest tones that the phase is set to the loudest mesurement on the spl .meter. - that's when you know you have the phase right to your mains.
Otherwise try 180 degrees

 

[Beatmatcher247]

It sounds great in that new location stacked. I turned them so the back of the subwoofer unit and the walls corner sort of makes an equilateral triangle that points toward the seating position. We'll see if I can stop driving them into clipping on that troublesome material after eq'ing when I get my Behringer.

I'm going to try some of my material that's been more problematic in the past this weekend. So far it sounds great. It vibrates the hell out of that bathroom door, and the shower door inside pretty bad. Can't wait to build a from the bottom up home theater room with proper accoustics, projection, and cable management in mind.

On my Marantz AV7005, I can figure out how to do multichannel music with sub, but am having difficulty figuring out how to turn on just the "sub and towers." I can't find away to turn subs on running in pure direct or stereo.